SPACE Newsletter

/

SE: PTE: M BE: R

1985

Frida y, Septe mber 20th, 7:30 PM Next meet ing: Frida y, Octob er 11th, 7:30 PM Octob er meet ing:

Bob Floyd Br-uce Haug Frank Haug Jim Schulz

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Edi torJon Nelson 487-262 7 Pr-esid ent • Tr-easu rer Max Feuer-. 774-622 6 Vice-Pr -es Cass Lib . Bruce Haug 774-622 6 Disk Lib. Secreta ry Steve Pauley Paper/E d. Lib. 537-544 2 473-289 7 SPACE/TAIG Bulleti n Board

Publis hed by the St. Paul Enthu siasts Compu ter Atari indepe ndent an (SPAC E), busine ss no with organ izatio n At ar i th i vJ on a f f i 1 i at i is ssion Permi . Incorp orated r simila any to grante d SPACE which with n organ izatio to newsl etters exchan ges this in ial mater reprin t howev er, newsl etter. We do, to the be t credi ask that . SPACE to and rs autho those Opinio ns expres sed are do and rs autho e articl of the the t reflec sarily neces not c 1 ub SPACE, c,f vi el1..1s Atari or rs, membe rs, office Inc.

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484-902 7 483-389 5 774-622 6 560-291 7

AT THIS MEETING: A BRODERBLt-lD SOFTWARE REPRESENTATIVE FEATURES IN THIS NEWSLETTER A REVIEW OF THE ACE C COMPILER PART III OF CHRIS CRAWFORD'S ASSEMBLY LANGUAGE COURSE PLUS PRES' BYTES, D.O.M. NEWS, AND AUG. MINUTES.

BYTES FROM THE PRES. by Bob Floyd

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month ✓ s This September Meeting meeting has been delayed 1 week so that a rep from Broderbund software cou l·d at tend both the SPACE and TAI G (The TAIG meeting wi 11 be 1 meetings. week early, on the same weekend as He will be showing software for us.) I have told the 400/800/XL/XE line. have an ST at the him that we will meeting, but I don ✓ t know wheth~r he There will bring any ST software. will be a doorprize. The Broderbund rep wi 11 al so be on the Computer· Tal ~< show on the 21st - 9:00 am on WWTC 1280.

October Meeting - We will have Charlie Marketing, Continental of Devine rep, at the manufacturer ✓ s ATARI ✓ s October meeting. He will be answering our questions and giving an ST demo. I hope to convince him to bring a Midi a for keyboard Casio Charlie was at the demonstration. last TAIG meeting and gave a very good Among the things I talk and demo. found out ar·e: - a double sided 3.5" drive for the ST will soon be here (perhaps already). - an 80 column (hardware) device will be available for the 130XE by 9/30. - the price of the 800XL will probably drop a little more. - the 10 megabyte ST hard disk will retail for $600 and should arrive by 9/30. - the DMA port on the ST can have up to 8 devices daisy-chained to it. So, have a CD-ROM, hard disk, you can (extra RAM?), etc. on this versatile 1.33 the Incidently, port. megabyte/second speed of this port enables the ST to do things (such as CD-ROM) that no other computer can do. This includes the AMIGA, Mac~ PC-AT. thin~: This sort of planning is why I ATARI will succeed. - the ST ROM chips will be available It will require 4 chips. by 10/15. - Asteroids, Missile Command and Star Raiders will be released on the ST. for $500. - the 260STD will retail single-sided This machine has the drive built in, but has only 256K <I feel foolish saying "only") and does It works on not come with a monitor. your TV, but only in low res 16 color, However, you can 40 column mode. still buy a monitor.

the CD-ROM machine wi l 1 retai 1 $599 and the encyclopedia disk for to $70. The early versions will They are to ship have pictures. September. - the dot matrix printer for the ST is quality The letter now shipping. version wi 11 be available soon. I···m sure this has stimulated some questions from you. B e ~ to write your guest ions down .QD. paper· and give them tc, me tl the September meeting. I wi 11 forwa.rd them to Charlie so that he 1.AJi 11 be able to have the anst-'Jers available at the October meeting. Our· terrific Meeting Room Saved meeting room has been saved thanks to Phyllis and Gordy at Wizard's Work. It appeared that we were not going to the r·oom, now that be all owed to use the room reservations changed to a Gord:,., different person at the "LI". the over at pulled some strings University that allowed us to keep the present room. Thanks a lot, Gordy! be Election Process Begins - We will electing a nominating committee of 2 It wi 11 be members at this meeting. their duty to nominate candidates for the club offices to be filled at the November meeting. They will report on October at the their nominations meeting, with elections planned for be electing a new November. We will and secretary VP, president, In addition, we need a new treasurer. a is This editor. newsletter Frank post/appointment. volunteer Haug, Jim Schultz <I finally spelled continue his name right), and I wi 11 in our posts as Disk Librarian, Paper Librarian and Analog Disk Librarian. I would like to add that if you are interested in being a club officer, phone please leave your name and the of or one me number with the nominating committee members at I wi 11 go over the election meeting. particulars at the meeting.

the Mindtools Authorized - Mindtools, new joint venture of Steve Pauley and is now an authorized Todd Burkey, ATARI dealer. Congratulations! Mapping the ATARI, revised - This book has finally arrived and is in the club It is essentially the same library. book with the same pages, except there are new appendices to cover the XL and

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I would buy it only if and er-r-ata. alr-eady own the or-iginal ver-sion. The book is gr-eat, but not that much betterthan the or-iginal. Dave Duber-man - Dave is ATARI ✓ s usergr-qup coor-dinator-. Afterseeing that SPACE was still not listed in the most I sent Dave a recent ATARI Explor-er-, copy of my previous 2 attempts to He registerthe club with ATARI. personally called me to apologize only He 2 days after I mailed the letter-. was really a nice guy. PI LOT Ref Gui de - Anyc,ne that bought fr-om language PILOT $3.00 the II 11 the get Computer Mai 1 Or·der did not out anyone I have 2 copies if manual. ther·e needs them. Ca I 1 me before the meeting if you want me to bring one foryou. 1024ST 1. - I noticed on Compuser-ve the other day' that someone has a 1 ready figured out how to upgrade a 520ST to It is an upgr-ade for 1024K RAM. har·dwar-e had{ers on I y at this point, but I think it for-eshadows things to come.

D.O.M. News by: Frank Haug We11 last month I had to get up on the ole ✓ soap box ✓ because of the lack of SPACE member submissions to Appear-ent1y no one read the DOM. it, or if they did, it wisked in one ear and ••• We are in dire need of (Some of member-written programs. you do write programs, don/t you?) If you donate a program to the DOM 1 ibrary, and we use it, you wi11 receive the DOM it is used on FREE! We11 this month, besides the be se 11 i ng the A. C. E. DOM, we w i 11 There is no DOS 'C ✓ language disk. on the disk because of lack of free pr-ograms the of One sector-s. written in C source has a bad sector in it but we hope to get a fix by the meeting. This is not a tutorial It w i 11 not teach you how to on C. It does recommend a program in C. 'helpful book' on learning C, and explains some differences between It will this and the Deep Blue C. be sold for $4.00 at the meeting.

Now on with the programs on the September 1985 D.O.M. 1. KINGKONG.BAS - You must avoid jump, jets and bar-rels as you run, and c1 imb open windows to get to the top. As soon as you get there, you race through Kong and reappear at over the bottom. Then you do it a11 again. 2. RACE - Use paddle to steer car while avoiding sides and other cars. 3. TAKE5 - An interesting game of skill for one playeragainst the computer. 4. QUEST - A dungeons & dragons type game with graphic display and playersaving features. Makes graphs 5. LINEGRAF.COM and allows you to print them and add data to them. 6. PICTRIX.BAS - Basic source of PICTRIX.COM, I put it out in case anybody wants to see how the program does what it does, and/or modify it. <Note in 1 ine 5100 you might have to change the char code depending on your printer, this is for chars. per inch. For the Gemini 10X you replace CHR$(24) with CHR$(16). On any other printer if the spacing isn't right replace the 24 with th proper c.p.i. number.) The print option should work with most Epson clones. a This is 7. PICTRIX.COM program compiled picture utility that allows you to load/save Koala Pad or Micro-Painter picture files, allowing you to convert one to the other. It also lets you make a hard copy of the file and, of cour-se, puts it on the screen.

The ACE C coapiler by Curtis S. Gibson

ACE C111as written by Ralph E. Walden of the Eugene, Oregon ATARI group (ACE), and is a descendant of the DEEP Bl.LE C coapiler fro11 APX by John Palevich. Both ACE C and DEEP Bl.LE C are descendants of a public d011ain C eo11piler by Ron Cain. The original C was Nritten for inhouse use at AT&T Bell Laboratories by Dennis Ritchie. ACE C is seai-public douin, ACE is letting SPACE sell it to the 11et1bers of SPACE to cover our production expenses. See Frank Haug at the Septl!llber SPACE aeeting for a copy. The C language, and this aeans anybody's C, is like an odd of asse11bler and higher level structured languages, like Pascal, It has a strong structured design like Pascal. It hn a set of si ■ple operations, or ccaands, like asseabler. The ■ix

set of operations is not small, but they are not in a short time.

■aster

i■po5sible

to

-4Froai these si111ple operations 10re eot1plex C01111ands, called functions can be built. Functions are Just like procedures in Pascal or subroutines in BASIC, they perfora a task. A function consists of one or many function calls, and the function code. A function call is the function naae and arg1111ents, and is eiaced in the nin progru code and executed like an expression 1n BASIC, The arg1.11ents are the variable naae(sl if any, and constant(sl if any, used by the function. An exa11ple: plraoveCn,M(nJ,y[nJ,shape(nJI, The code of the function is not li~ted in the main progru, it is listed and eo11piled before the main prograni, The code of a function consists of the function name, argu111ents if any, arg1111ent declarations if any, an opening delimiter character(sl, otfier declarations if any, executable expressions (these 1ay be functions or si ■ple operations>, and a closing delimiter character(sl, If descriptive function na■es are used, the main listing reads like a psuedo-code algorith■, Exampl~ of tasks for a function 110uld be; input fro■ keyboard, write to screen, printer output, read fr011 ,'.ck, Nrite to disk, perfor■ ing a Math function, controlling a loop, sorting ~ list, testing a condition, fornsat a record, searching a list, 1ncrement-decreNnt a counter or value, ■ove a value to a neN location in Me110ry, ect, You can build up a library of functions that you can use in other programs, and save writing the code again and again, . C uses tNO types of statenients simple and co■pound, A s11ple statement 1s a s~ngle line of code 1 like~ ~ine of BASIC. The co■pour.d statement 1s made of an opening del11111ter character(sl braces on the aain fra11e C or S( with ACE C1 a block of two or more si ■ple or co■ pound statements and the closing delimiter character(s) braces or Sl with ACE C. The compound statement is like a line of BASIC coaands separated by semicolons, they will all be executed (unless you Juap over so■e of them). This cotpound statement gives C the poNer to be Nritten in a structured Nay. Chas a control structure that is not available in most BASICs, the WHILE loop. The while loop is SOiie what like the for loop, but it dernds on a conditional expression rather than a ~ounter to contro the exit fro■ the loop. Exa■ple; wh1le(total(= 111101 $( state11ent $) , this Mhile loop NOuld execute the next state11ent until the total becaae larger than 100,

ACE C and DEEP BUE C are P-code compilers. 11\en the is compiled it is converted into instructions (called p-code) for a small machine language progru called a run-ti ■e interpreter. This p-code is not 6502 uchine l~uage and is not as fast as an assembly language progra■, but 1t 1s faster than BASIC. progra■

When you get your copy of ACE C ■ake a listing of all the •TXT files, you can't learn C from thetn, but you can learn to use the ACE C, To use the ACE C first aake a 110rk disk, Put on the work disk the files: DOS.SYS1 _DUP.SYS, ACEC.CIJI, LINK.CD!, FASTC,CQIII, Cf'ORMAT.COM, ENGINE.Ow, and ENGLOAD.OBJ. Work from the work disk only, if you ■ake an error the progrilllS can Nipe out the disk tit can happen folks!). You Nill also need a word processer or text editor. The BASIC cartridge or Asse■bler Editor cartridge will not work as the text editor. The first step is to design your progra■, think first-act later. Second, key it in with the text edito~t..!iving it under the name you choose with the •,c• extension: IHl:.,C. Third, enter the DOS type L (for Load File>, press the RETURN key type in ACEC.COM and press the RETURN key. The Co■piler Nih be loaded and ask for the naae of the file to be co■piled, The eo11piler takes your file called the source code and translates it into p-code putting it under the filenaae with the extension ",CCC"t this is called relocatable code, the progra■ is not yn ready o run. The source code file is not changed, if you need to add to or chanue rour progra■ you will have to use the text editor on the •.c file and recoapile it. The eo11piler can take a few seconds to many minutes to eo11pile a program, typically about a 1inute. The forth step is to create a neN file with the •,Lit(• extension, This file is a list of files the linker Nill put together to make the executable code• the relocatable code of your program, the relocatable code of the function library if there is orre, and the last file Must always be the run-ti•

interpreter ENGINE.OBJ or ENBLOAD,OBJ, Fifth step, load t file LIN<.COII! with a DOS option L like the coapiler, and ent the file naae. The linker will run for about a ■ inute, creati the executable code file with a •,eot• extension, Finally to run the program do a DOS option L of the executable code file: FNAl'IE.COM. The e><ecutable code can be aoved to other disks and run from DOS option L. A given program written in C Nill run faster than the sa■e program written 1n BASIC. If you use a library of functions and use structured design, you Nill be able to write code faster with less effort. Some books on the C language are: The C Pro~uai~ Lan,ua~e by Brain W. Kernighan and Dennis M. Rit ie,ing fr0111 MSC o C by Robert J. Traister, Learning to Pro9ru 1n Cby Thoaas Plu111 The C Primer by Les Hancock and Morris Krieger The C Pro~ra•in~ Tutor by Leon A. Wortun and Tho■os O. Sidebohoa, and t e one use The C Progra1111er's Handbook by Thom Hogan. All of these books are in print and available at larger book stores.

August meeting minutes By Joanne Floyd The last SPACE meeting was held on August 9, with 90 people in attendance. During the President's report, Bob Floyd discussed the possibility that the club may need to find a new meeting room. He also reminded members that the officer election process begins in September. In the Vice President's report, Bruce Haug asked members to submit programs for the disk of the month, reminding us that the supply of public domain programs is 1 imi ted. He a 1 so discussed his appearance on the Sunday morning computer show (Computer Line) on ~c . Phyllis and Gordy from Wizard's Work next reviewed their meeting with the new ATARI rep in the Twin Cities. At this meeting, they were shown several soon-to-be-released ST programs such as a wordprocessor, spreadsheet, and database master. They were particularly impressed by the RGB monitor. Gordy mentioned that ATARI seems to be committing itself to the ST and hardware development, leaving software development to third parties. Todd from Mindtools then demonstrated the 520 ST, pointing out such features as the screen editor, windows, and desktop programs. He believes that the 520 compares very favorably to the MacIntosh in terms of speed, useability, and general functioning.

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With regard to new business, Bruce Haug said that the club is planning to purchase a printer ribbon re-inV.er that will re-inV. 951/. of commercially available ribbons. Members would be charged a minimal fee for this service. With regard to BBS information, he announced that the BBS password file has been sabotaged so people may need to re-register for passwords. At the end of the meeting, Bob demonstrated his label-maV.er program. <See the last newsletter for a description of this program.) He also demonstrated two APX programs available from Antic. Mars Mission II is a cross between the arcade game Scramble and the classic computer game Caverns of Mars. King Tut ✓ s Tomb is similar to the arcade game Tutankhamen. Bob considers this second game a very good value at $15 because it includes several different series of mazes, many of which are quite challenging. It also includes a "tomb construction set• which allows you to develop your own mazes.

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REPRINTED BY PERMISSION. CHP I:::; CPA/-•.JFOF:D A:::;:::;Et-JBL·( LAHGUh(3E

COURSE - LESSON 3: LOGIC BOOLEAt·-l l0(3 IC

A great deal of programming involves the use of Boolean logic. This is a standardized system for ~, ,=:1. n d 1 i n g 1 o g i c -:1. i m ·='· n i p u 1 a. t i on s. • I t ·· s sort of like algebra for logic. You must understand Boolean logic if you are to write assembly language programs, so let's get started. Where algebra d~als with numbers, Boolean logic deals with propositions~ A proposition is just a statement such ·='· ·=· "Fr· ed e.:;,. t ·=· ,_. ..1or·m·:::=.. " It c .:i.n t .:.d< i::• only two possible values -- True or False. In our programs we seldom bother with broad and glorious propositions such as "Love is the uni .._,..er· s.:i.1 i .:;,.n ,;:iu .:i.ge of tr· u th" or· "(,.J.:1.r· is the extension of pol icy by other means". Instead, we normal Jy deal with propositions such as "The .iO\'·=·tick: tr·i,;i,;;ier, h-:1.s t,een pr·es·::-ed," or· "There is a disk:ette in the ·disk dr· i i../e.

RIBBON RE-INKER SPACE is consider· i ng the purchase c,..,: a printer ribbon r-e-inker-. Befor-e we go ahead with this purchase, we need the following information from the membership: Members Name PrinterBrand PrinterModel Ribbon# used Please turn this information in ONLY IF YOU ARE INTERESTED in having your ribbons re-inked for approximately $1.00. Turn in to Bruce Haug V.P. at the Sept. meeting. I will have samples of pr-inting the done with this re-inker at meeting. the It looks good to me, sample printing was done with a r-ibbon re-inked 36 times.

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When we use Boolean logic with ~omputer, we may think in terms true ~nd false, but the computer actually working with l's and 0's. u ·:::.e the f ,:, I 1 01,,._; i n g c on•-./en ti on : ·='· corresponds to a Boolean value "tr·ue", v..1h i 1 e a, (1 correspons to E:c)o l e.:1.n

II f .::i.1 ·:.ell .

a of

is We 1

of a

Using this system we can represent propositions inside the computer. However, programming requires more than the mere representation of data; we must also be able to manipulate that data. This brings us to the Boolean operators. There are four common Boolean operations necessary for most programming practices: 1)

Not

This is the simplest of Boolean operators. It takes a single Boolean value as an input and produces as its output the 1 OQ 1 c -:i.1 c on\,..er· se of the input. Thus, a true input yields output 9 while a false input generates

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a. tr·ue input. 2) Or·

takes two This Boolean operator and its input Boolean values as generates a single Boolean value as its output. The value of the output the values of the inputs depends on If according to the following rule: one input is true OR the other value is true. the output then is true, Other·v.1i·:-e, the output i-::. fa.l s.e. 3) And

like This Boolean operator is just the or-operator, except that it uses a r· u 1 e is: If c,n e I t ·=· differ· en t r· u 1 e. is input is true AND the other input true; is the output then true, otherwise the output is false. 4)

Exclus.ive-Or

This Boolean operator is just 1 ike the or-operator, except that its rule i ·=·: If one input is. tr·ue, OF: the c,ther· input is true, BUT not both are true, otherwise, then the output is true; the output 1s false. Boolean When we use the 6502 for the that operations, you must remember wide. bits eight operations are Instead of working with one bit at a time, we use all eight bits of a word in p.:i.r· .:;. 1 1 e 1 • The bi ts in a. b'./ t e .ar· e independent and do not affect each other in any way -- at least as far as Boolean operations are concerned. The 6502 has three instructions for performing Boolean operations. These The first and ORA. EOR, are AND, For· and-operation . an per· f or·m·;;. code: lowing fol the example, consider LDA AND

FISH GOAT

the Load first will This accumulator with the value of FISH. the It 1.'.li 11 then And the content·;;. of accumulator with the contents of GOAT. the and-operation will The result of be left in the accumulator. an The AND-instruct ion can use just immediate operand if you desire, as the ADC-instruct ion can. The

EOR-instruct ion

provides

ttie

It worKs exclusive-or operator. The like the AND-instruct ion. the rrovides instruction in just the same way. the obtain to wish you If this #SFF; EOR use just n, NOT-operatio the in bit e.:ech i n·..,..•er· t 11Ji 11 easily so is NOT Because accumulator. no ther·e is. r·epr·oduced ,..-.Ji th EOF:, special NOT instruction in the 6502. APPL~CATIONS OF BOOLEAN LOGIC I+ /OU h .:e.'v'e ,:<.n './ sen ·:.e at a. l 1 , /OU are probabl/ asking, "What good is ·='· i 1 What would I this Boolean nonsense? applications Four use it for?" a•..,..•a. i 1 .:e.b 1 e:

Many times our programs encounter r· ·='· t h e r· c c,m p 1 e :,-: l o g i c ·='· 1 ·=· i f.: u ·='· t i on '=· • Th e program must be able to load a file; if the FMS is in place and there is ~ the disk drive, and the diskette in file we are lookino the has diskette for· , c,r· the f i 1 e ·;;.pee i f i ca.ti on c .al 1 ·~. for· .:1. c.:1.·::.set te 1 0.:1.d, then t.,.1e t.,.1i 11 1c,a.d the program. Many programming problems operations, Boolean such involve is certain!/ a Keeping them straight hea.da.che. 2)

M.:1.sking Bi ts

isolate to need Sometimes we For a b/te. particular bits in I ( 19 4 1) e :,: a.mp l e , i n Ea s t er· n Fr· on t used the character value to store the unit type. The color of the unit was the encoded in the upper two bits of b;,..te, the t;,,pe in the l m•..1er· ·::.f::.: bit·::.. If I wanted to get onl:,.. the unit h,.10 type, I had to mask out the upper· bits. This I did with t h e f o 1 1 c,1. ,.1 i n g code fr· agmen t: LDA AND

UNITCODE M·$3F

The AND-instruct ion eliminated the lea.•-. dng me ,,..dth just upper· ti....rn bits, this i t -m .as~: i n •;;) 1 i I< e 8 . e p :/ . ' t t i n t he u u·=·e L••Je ·:-itua.tion·=·· i·=- useful in ma.ny it frequently when we pack bits into a byte to save memory. It is also handy to If you want with input handling. read the joystick port, you frequently mask out the bits in turn to see which is -~.cti••./e.

-7B)'·· the v,1ay, you mask out bits set You o 1 v-.1ith the AND-instruction. ma·;;k out bits set to 0 with the ORA The logic is reversed. i n-:.tr·uc ti on. Settin,;i

:3)

-::<.nd

Cle.:1.r·ing

Individu-::<.1

Bits ORA We also use the AND and c 1 ear· instructions or to set i ndivi dua.1 bi ts ~•,ti thin a b;,•·te. Thi·=· is most often useful for handling arrays of flag bits. 4)

Folding Bytes Together

This 1 it t 1 e fr·.agmen t fold bytes together: LDA EOR AND EOR '.3TA

c,f code

1.,•.d

·instructions, except that the bit that gets shoved into the bottom is not necessarily a zero; it is the contents of the Carry bit. The bit that gets pushed off the edge of the byte goes into the Carry bit, so it is not lost. Thus, if you rotate either way nine times, you'l 1 be right back where you -:.tar· ted. Rotate instructions are a handy way to get a particular bit into the carry bit where you can work on it. Conversely, once you get your desired bit into the carry bit the way you want it, you can put it back into a byte with some rotate instructions.

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FISH GOAT MAS~: GOAT ANSi-•JER

This is a ma9 i cal piece of code. See if you can fiqure out what it doe·=·. E;( per· i men t! i.,•.1 it t-1 t1.,,10 'v'a 1 u es of MAS~<: $OF a.nd $-FD. SHI FT AND ROTATE INSTRUCT I Ot·•J:::; The 6502 also has instructions that allow you to shift the bits around inside a byte. The first of these are the -:-hi ft ,i nstr·uc ti c,ns. One, A:3L, shifts a b;lte to tr,e left; the other·, LSR, shif~s a byte to the right. Thus, the byte %01101011, when shifted left, becomes ~11010110. Each bit is shified one p~;ition to the left. The leftmost bit is rudely pushed right out of the byte and falls away ("Aaaaaaaaarrrrrggggg!"). A zero is shifted into the ri9htmost bit. The LSR instruction does the same thing in the opposite direction. Note that ASL also doubles the value of the byte, while LSR halves it. Two ASL's multiply by four; three multiply by eight. This makes it easy to do simple multiplication, but be careful with round-off error here. What happens if you try to multiply by 256? What do you get if you halve 3? A •v•ar· i a.ti on on shift the i n-:.tr·uc ti on-:. r·c,t.:i.te ar·e the There a.re tt,-.1c,: i n-:.tr·uc ti c,n·;;. rota.te ( F.:OR) . 1 ef t ( ROU .:1.nd r· o t ·='· t e r· i gh t These function .ju·;;t 1 ike the shift

INCREMENT AND DECREMENT INSTRUCTIONS are the increment and decrement instructions. These allow you to add one (increment) or subtract one (decrement) from a memory location. These are not considered to be arithmetic operations so they do not affect the Carry flag, nor are they -:1.ffected b'.i it. You cannot increment or decrement the accumulator, onl; RAM locations.

HELPFUL HINT Reprinted from the 6/85 issue of HACK the newsletter Atari Anonymous of Rhode Island. If you want to change something in your BASIC program that has been repeated many times, such as changing every GOTO to a GOSUB, their is an alternative way to just searching through the listing and manually changing every line. As you can imagine, this can be a "Royal Pain" with long programs, What you do is first LIST the program to disk+ Then boot your word processor and load the LISTED file into memory, Now you can treat the file like a "text file" and do a "search and replace" to change your commands or whatever you want, When you are done "editing" your BASIC program save it back to disk. Now re-boot BASIC and "ENTER" the file into memory, List it and now you will see the changes you have made,

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WANT ADS

B & [] H□rnE c□mPLITEA SUPPUES

possible for members to place_ The ads may be ✓ want Ads ✓ in this newsletter. software, used hardware, used for selling that anything about just or services, tutoring as are rates The Atari. with has to do follows: $1 .00 216 Letters 6 Lines .25 36 Letters Line 1 It is

The following is a list of ad1)ertising rates for vendors or individual members. Full page $18.00 7-1/2" X 10" 10.00 3-5/8" X 10" Half page 10.00 7-1/2" X 5" page Half 5. 50 3-5/8" X 5 11 page 1/4 All advertiseme nts must be paid for when they are submitted. Deadline for ad placement To place is two Mondays before the meeting. ad or for more info, call the editor.

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SSDD FLOPPYS 10 FOR $8.90 BUTTONS S.50 EA 350 TO CHOOSE FROM

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630 Ashland Av. St. Paul, Mn. 55104

Meeting site: U of M St, Paul campus Office Classroom Bldg. rooms B-35 St. Paul, Minnesota

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